@page "/scripts"
@attribute [Authorize(Policy = AdminUiPolicies.ConfigEditor)]
@rendermode RenderMode.InteractiveServer
@using Microsoft.EntityFrameworkCore
@using ZB.MOM.WW.OtOpcUa.Configuration
@using ZB.MOM.WW.OtOpcUa.AdminUI.ScriptList
@inject IDbContextFactory<OtOpcUaConfigDbContext> DbFactory

<PageErrorBoundary>
<div class="d-flex justify-content-between align-items-center mb-3">
    <h4 class="mb-0">Scripts</h4>
    <a href="/scripts/new" class="btn btn-primary btn-sm">New script</a>
</div>

@if (_rows is null)
{
    <p>Loading…</p>
}
else
{
    <section class="panel rise mt-3" style="animation-delay:.08s">
        <div class="panel-head">@_rows.Count script@(_rows.Count == 1 ? "" : "s")</div>
        @if (_rows.Count == 0)
        {
            <div style="padding:1rem" class="text-muted">No scripts defined.</div>
        }
        else
        {
            <table class="table table-sm mb-0 align-middle">
                <thead>
                    <tr>
                        <th>Script</th>
                        <th></th>
                    </tr>
                </thead>
                <tbody>
                    @foreach (var s in _rows)
                    {
                        <tr>
                            <td>
                                <div>
                                    <span>@(string.IsNullOrWhiteSpace(s.Name) ? s.ScriptId : s.Name)</span>
                                    <span class="chip chip-idle ms-1">@s.Language</span>
                                </div>
                                <div class="mono small text-muted">
                                    @s.ScriptId · hash=@DisplayText.Abbreviate(s.SourceHash, 12)
                                </div>
                            </td>
                            <td class="text-end">
                                <div class="btn-group btn-group-sm" role="group">
                                    <button type="button" class="btn btn-sm btn-outline-secondary"
                                            @onclick="() => ShowSource(s.ScriptId)">Source</button>
                                    <a href="/scripts/@s.ScriptId" class="btn btn-sm btn-outline-primary">Edit</a>
                                </div>
                            </td>
                        </tr>
                    }
                </tbody>
            </table>
        }
    </section>
}

@* The dialog's EXISTENCE is gated on the held id (operator intent); the resolve drives only its
   CONTENT. Gating existence on FindSourceScript() would make the modal a function of _rows, and any
   render where the row is momentarily unresolvable (a future reload/poll setting _rows null or
   replacing the list) would unmount the subtree and dispose the Close handler's binding id — a
   click already in flight then throws GetRequiredEventBindingEntry. Latent today (_rows is written
   once, in OnInitializedAsync) but the shape bit ScadaBridge live the moment a refresh landed. *@
@if (_sourceScriptId is not null)
{
    var src = FindSourceScript();
    <div class="modal-backdrop fade show" style="display:block"></div>
    <div class="modal fade show" tabindex="-1" role="dialog" style="display:block">
        <div class="modal-dialog modal-lg modal-dialog-scrollable" role="document">
            <div class="modal-content">
                <div class="modal-header">
                    <h5 class="modal-title">
                        @if (src is not null)
                        {
                            @(string.IsNullOrWhiteSpace(src.Name) ? src.ScriptId : src.Name)
                            <span class="mono small text-muted ms-2">@src.ScriptId</span>
                        }
                        else
                        {
                            <span class="mono">@_sourceScriptId</span>
                        }
                    </h5>
                    <button type="button" class="btn-close" aria-label="Close" @onclick="CloseSource"></button>
                </div>
                <div class="modal-body">
                    @if (src is null || (_sourceLoaded && _sourceCode is null))
                    {
                        <p class="text-muted mb-0">This script is no longer loaded.</p>
                    }
                    else if (!_sourceLoaded)
                    {
                        <p class="text-muted mb-0">Loading source…</p>
                    }
                    else
                    {
                        <pre class="mono small mb-0" style="background:var(--zebra-bg);padding:1rem;border-radius:4px;overflow:auto">@_sourceCode</pre>
                    }
                </div>
                <div class="modal-footer">
                    <button type="button" class="btn btn-outline-secondary" @onclick="CloseSource">Close</button>
                </div>
            </div>
        </div>
    </div>
}
</PageErrorBoundary>

@code {
    // A projection without SourceCode (R04 P8); the source loads per dialog open.
    private List<ScriptListRow>? _rows;

    // Only the id of the script whose source dialog is open — never the record itself, so a reload
    // that drops or replaces the row cannot leave a stale object on screen.
    private string? _sourceScriptId;

    // The open dialog's source, fetched on open. _sourceGeneration discards a superseded fetch (the
    // operator opened another row, or closed the dialog, while the first one was in flight).
    private string? _sourceCode;
    private bool _sourceLoaded;
    private int _sourceGeneration;

    protected override async Task OnInitializedAsync()
    {
        await using var db = await DbFactory.CreateDbContextAsync();
        _rows = await ScriptListQueries.LoadRowsAsync(db);
    }

    /// <summary>Re-resolves the open dialog's script from the current list on every render. Drives
    /// the dialog's CONTENT only — never its existence (see the comment at the markup): a script
    /// that is no longer loaded renders a notice with the frame and Close still mounted.</summary>
    private ScriptListRow? FindSourceScript()
        => _sourceScriptId is null
            ? null
            : _rows?.FirstOrDefault(s => s.ScriptId == _sourceScriptId);

    // One dialog at a time: opening another row replaces the id.
    private async Task ShowSource(string scriptId)
    {
        var generation = ++_sourceGeneration;
        _sourceScriptId = scriptId;
        _sourceCode = null;
        _sourceLoaded = false;

        await using var db = await DbFactory.CreateDbContextAsync();
        var source = await ScriptListQueries.LoadSourceAsync(db, scriptId);
        if (generation != _sourceGeneration) return;
        _sourceCode = source;
        _sourceLoaded = true;
    }

    private void CloseSource()
    {
        _sourceGeneration++;
        _sourceScriptId = null;
        _sourceCode = null;
        _sourceLoaded = false;
    }
}